An unexpected error has occurred. Your purchase has not been completed. Please contact Steam Support.
When attempting a purchase through the Steam Store, I am getting the following exact error message:
An unexpected error has occurred. Your purchase has not been completed. Please contact Steam Support.
How can I complete my purchase?
If the specific error message that you receive is one of the following instead, follow the link to the correct support page for that issue.
Your purchase has not been completed. Your credit card information has been declined by your credit card company due to an incorrect address being entered.
Your credit card information has been declined by your credit card company
An unexpected error has occurred. Your purchase has not been completed. Please contact Steam Support.
This error can occur when our system has encountered an issue with the transaction that you are attempting to make.
Test the issue once or twice more, ensuring that you are entering the correct billing information. Avoid spamming failed purchase attempts more than a few times.
If you continue to encounter this error, please contact Steam Billing and Support with your Steam account's login name and we will assist you further.
VPN/Proxies
Disable or completely remove any IP proxy or VPN software that you may be using, restart your computer, and test your purchase again. All transactions that are initiated through anonymous proxies will be declined by Steam.
Submitting a Steam Support ticket
What information should I include with my Steam Support ticket?
Tips for submitting a Steam Support ticket
Always provide your Steam account's login name when submitting a Steam Support ticket.
Ensure that you provide the name of the game(s), addon(s) or applications that you are trying to purchase.
Categorize your ticket in the Purchases and Payment category.
If the issue is resolved and your ticket is still open, log in to your Steam Support account and close your ticket.
Failure to provide all necessary information when submitting a ticket can only cause a longer delay before your issue is resolved.